Displaying publications 21 - 40 of 161 in total

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  1. The two mutations of actin-myosin interface and their effect on the dynamics, structures, and functions of skeletal muscle actin
    Sadat Mohajer F, Parvizpour S, Razmara J, Shahir Shamsir M
    J Biomol Struct Dyn, 2019 Feb;37(2):372-382.
    PMID: 29338614 DOI: 10.1080/07391102.2018.1427630
    Congenital myopathy is a broad category of muscular diseases with symptoms appearing at the time of birth. One type of congenital myopathy is Congenital Fiber Type Disproportion (CFTD), a severely debilitating disease. The G48D and G48C mutations in the D-loop and the actin-myosin interface are the two causes of CFTD. These mutations have been shown to significantly affect the structure and function of muscle fibers. To the author's knowledge, the effects of these mutations have not yet been studied. In this work, the power stroke structure of the head domain of myosin and the wild and mutated types of actin were modeled. Then, a MD simulation was run for the modeled structures to study the effects of these mutations on the structure, function, and molecular dynamics of actin. The wild and mutated actins docked with myosin showed differences in hydrogen bonding patterns, free binding energies, and hydrogen bond occupation frequencies. The G48D and G48C mutations significantly impacted the conformation of D-loops because of their larger size compared to Glycine and their ability to interfere with the polarity or hydrophobicity of this neutralized and hydrophobic loop. Therefore, the mutated loops were unable to fit properly into the hydrophobic groove of the adjacent G-actin. The abnormal structure of D-loops seems to result in the abnormal assembly of F-actins, giving rise to the symptoms of CFTD. It was also noted that G48C and G48D did not form hydrogen bonds with myosin in the residue 48 location. Nevertheless, in this case, muscles are unable to contract properly due to muscle atrophy.
    Matched MeSH terms: Protein Conformation*
  2. Conformational destabilization of Bacillus licheniformis α-amylase induced by lysine modification and calcium depletion
    Tan CY, Rahman RN, Kadir HA, Tayyab S
    Acta Biochim. Pol., 2011;58(3):405-12.
    PMID: 21887412
    Bacillus licheniformis α-amylase (BLA) was chemically modified using 100-fold molar excess of succinic anhydride over protein or 0.66 M potassium cyanate to obtain 42 % succinylated and 81 % carbamylated BLAs. Size and charge homogeneity of modified preparations was established by Sephacryl S-200 HR gel chromatography and polyacrylamide gel electrophoresis. Conformational alteration in these preparations was evident by the larger Stokes radii (3.40 nm for carbamylated and 3.34 nm for succinylated BLAs) compared to 2.43 nm obtained for native BLA. Urea denaturation results using mean residue ellipticity (MRE) as a probe also showed conformational destabilization based on the early start of transition as well as ΔG(D)(H(2)O) values obtained for both modified derivatives and Ca-depleted BLA. Decrease in ΔG(D)(H(2)O) value from 5,930 cal/mol (for native BLA) to 3,957 cal/mol (for succinylated BLA), 3,336 cal/mol (for carbamylated BLA) and 3,430 cal/mol for Ca-depleted BLA suggested reduced conformational stability upon modification of amino groups of BLA or depletion of calcium. Since both succinylation and carbamylation reactions abolish the positive charge on amino groups (both α- and ε- amino), the decrease in conformational stability can be ascribed to the disruption of salt bridges present in the protein which might have released the intrinsic calcium from its binding site.
    Matched MeSH terms: Protein Conformation
  3. The role of alternative salt bridges in cold adaptation of a novel psychrophilic laminarinase
    Parvizpour S, Razmara J, Shamsir MS, Illias RM, Abdul Murad AM
    J Biomol Struct Dyn, 2017 06;35(8):1685-1692.
    PMID: 27206405 DOI: 10.1080/07391102.2016.1191043
    Matched MeSH terms: Protein Conformation
  4. Molecular dynamics study of the structure, flexibility and dynamics of thermostable l1 lipase at high temperatures
    Abedi Karjiban R, Abdul Rahman MB, Basri M, Salleh AB, Jacobs D, Abdul Wahab H
    Protein J, 2009 Jan;28(1):14-23.
    PMID: 19130194 DOI: 10.1007/s10930-008-9159-7
    Molecular Dynamics (MD) simulations have been used to understand how protein structure, dynamics, and flexibility are affected by adaptation to high temperature for several years. We report here the results of the high temperature MD simulations of Bacillus stearothermophilus L1 (L1 lipase). We found that the N-terminal moiety of the enzyme showed a high flexibility and dynamics during high temperature simulations which preceded and followed by clear structural changes in two specific regions; the small domain and the main catalytic domain or core domain of the enzyme. These two domains interact with each other through a Zn(2+)-binding coordination with Asp-61 and Asp-238 from the core domain and His-81 and His-87 from the small domain. Interestingly, the His-81 and His-87 were among the highly fluctuated and mobile residues at high temperatures. The results appear to suggest that tight interactions of Zn(2+)-binding coordination with specified residues became weak at high temperature which suggests the contribution of this region to the thermostability of the enzyme.
    Matched MeSH terms: Protein Conformation
  5. Crystal structure of a neoagarobiose-producing GH16 family β-agarase from Persicobacter sp. CCB-QB2
    Teh AH, Fazli NH, Furusawa G
    Appl Microbiol Biotechnol, 2020 Jan;104(2):633-641.
    PMID: 31784792 DOI: 10.1007/s00253-019-10237-y
    PdAgaC from the marine bacterium Persicobacter sp. CCB-QB2 is a β-agarase belonging to the glycoside hydrolase family 16 (GH16). It is one of only a handful of endo-acting GH16 β-agarases able to degrade agar completely to produce neoagarobiose (NA2). The crystal structure of PdAgaC's catalytic domain, which has one of the highest Vmax value at 2.9 × 103 U/mg, was determined in order to understand its unique mechanism. The catalytic domain is made up of a typical β-jelly roll fold with two additional insertions, and a well-conserved but wider substrate-binding cleft with some minor changes. Among the unique differences, two unconserved residues, Asn226 and Arg286, may potentially contribute additional hydrogen bonds to subsites -1 and +2, respectively, while a third, His185 from one of the additional insertions, may further contribute another bond to subsite +2. These additional hydrogen bonds may probably have enhanced PdAgaC's affinity for short agaro-oligosaccharides such as neoagarotetraose (NA4), rendering it capable of binding NA4 strongly enough for rapid degradation into NA2.
    Matched MeSH terms: Protein Conformation
  6. Haloadaptation: insights from comparative modeling studies between halotolerant and non-halotolerant dehalogenases
    Edbeib MF, Aksoy HM, Kaya Y, Wahab RA, Huyop F
    J Biomol Struct Dyn, 2020 Aug;38(12):3452-3461.
    PMID: 31422756 DOI: 10.1080/07391102.2019.1657498
    Halophiles are extremophilic microorganisms that grow optimally at high salt concentrations by producing a myriad of equally halotolerant enzymes. Structural haloadaptation of these enzymes adept to thriving under high-salt environments, though are not fully understood. Herein, the study attempts an in silico investigation to identify and comprehend the evolutionary structural adaptation of a halotolerant dehalogenase, DehHX (GenBank accession number: KR297065) of the halotolerant Pseudomonas halophila, over its non-halotolerant counterpart, DehMX1 (GenBank accession number KY129692) produced by Pseudomonas aeruginosa. GC content of the halotolerant DehHX DNA sequence was distinctively higher (58.9%) than the non-halotolerant dehalogenases (55% average GC). Its acidic residues, Asp and Glu were 8.27% and 12.06%, respectively, compared to an average 5.5% Asp and 7% Glu, in the latter; but lower contents of basic and hydrophobic residues in the DehHX. The secondary structure of DehHX interestingly revealed a lower incidence of α-helix forming regions (29%) and a higher percentage of coils (57%), compared to 49% and 29% in the non-halotolerant homologues, respectively. Simulation models showed the DehHX is stable under a highly saline environment (25% w/v) by adopting a highly negative-charged surface with a concomitant weakly interacting hydrophobic core. The study thus, established that a halotolerant dehalogenase undergoes notable evolutionary structural changes related to GC content over its non-halotolerant counterpart, in order to adapt and thrive under highly saline environments.Communicated by Ramaswamy H. Sarma.
    Matched MeSH terms: Protein Conformation, alpha-Helical
  7. Structure-informed separation of bioactive peptides
    Acquah C, Chan YW, Pan S, Agyei D, Udenigwe CC
    J Food Biochem, 2019 01;43(1):e12765.
    PMID: 31353493 DOI: 10.1111/jfbc.12765
    The application of proteomic and peptidomic technologies for food-derived bioactive peptides is an emerging field in food sciences. These technologies include the use of separation tools coupled to a high-resolution spectrometric and bioinformatic tools for prediction, identification, sequencing, and characterization of peptides. To a large extent, one-dimensional separation technologies have been extensively used as a continuous tool under different optimized conditions for the identification and analysis of food peptides. However, most one-dimensional separation technologies are fraught with significant bottlenecks such as insufficient sensitivity and specificity limits for complex samples. To address this limitation, separation systems based on orthogonal, multidimensional principles, which allow for the coupling of more than one analytical separation tool with different operational principles, provide a higher separation power than one-dimensional separation tools. This review describes the structure-informed separation and purification of protein hydrolyzates to obtain peptides with desirable bioactivities. PRACTICAL APPLICATIONS: Application of bioactive peptides in the formulation of functional foods, nutraceuticals, and therapeutic agents have increasingly gained scholarly and industrial attention. The bioactive peptides exist originally in protein sources and are only active after hydrolysis of the parent protein. Currently, several tools can be configured in one-dimensional or multidimensional systems for the separation and purification of protein hydrolyzates. The separations are informed by the structural properties such as the molecular weight, charge, hydrophobicity or hydrophilicity, and the solubility of peptides. This review provides a concise discussion on the commonly used analytical tools, their configurations, advantages and challenges in peptide separation. Emphasis is placed on how the structural properties of peptides assist in the separation and purification processes and the concomitant effect of the separation on peptide bioactivity.
    Matched MeSH terms: Protein Conformation
  8. Comparative modelling studies of fruit bromelain using molecular dynamics simulation
    Pang WC, Ramli ANM, Hamid AAA
    J Mol Model, 2020 May 16;26(6):142.
    PMID: 32417971 DOI: 10.1007/s00894-020-04398-1
    Fruit bromelain is a cysteine protease accumulated in pineapple fruits. This proteolytic enzyme has received high demand for industrial and therapeutic applications. In this study, fruit bromelain sequences QIM61759, QIM61760 and QIM61761 were retrieved from the National Center for Biotechnology Information (NCBI) Genbank Database. The tertiary structure of fruit bromelain QIM61759, QIM61760 and QIM61761 was generated by using MODELLER. The result revealed that the local stereochemical quality of the generated models was improved by using multiple templates during modelling process. Moreover, by comparing with the available papain model, structural analysis provides an insight on how pro-peptide functions as a scaffold in fruit bromelain folding and contributing to inactivation of mature protein. The structural analysis also disclosed the similarities and differences between these models. Lastly, thermal stability of fruit bromelain was studied. Molecular dynamics simulation of fruit bromelain structures at several selected temperatures demonstrated how fruit bromelain responds to elevation of temperature.
    Matched MeSH terms: Protein Conformation
  9. Evaluating the performance of MM/PBSA for binding affinity prediction using class A GPCR crystal structures
    Yau MQ, Emtage AL, Chan NJY, Doughty SW, Loo JSE
    J Comput Aided Mol Des, 2019 05;33(5):487-496.
    PMID: 30989574 DOI: 10.1007/s10822-019-00201-3
    The recent expansion of GPCR crystal structures provides the opportunity to assess the performance of structure-based drug design methods for the GPCR superfamily. Molecular Mechanics/Poisson-Boltzmann Surface Area (MM/PBSA)-based methods are commonly used for binding affinity prediction, as they provide an intermediate compromise of speed and accuracy between the empirical scoring functions used in docking and more robust free energy perturbation methods. In this study, we systematically assessed the performance of MM/PBSA in predicting experimental binding free energies using twenty Class A GPCR crystal structures and 934 known ligands. Correlations between predicted and experimental binding free energies varied significantly between individual targets, ranging from r = - 0.334 in the inactive-state CB1 cannabinoid receptor to r = 0.781 in the active-state CB1 cannabinoid receptor, while average correlation across all twenty targets was relatively poor (r = 0.183). MM/PBSA provided better predictions of binding free energies compared to docking scores in eight out of the twenty GPCR targets while performing worse for four targets. MM/PBSA binding affinity predictions calculated using a single, energy minimized structure provided comparable predictions to sampling from molecular dynamics simulations and may be more efficient when computational cost becomes restrictive. Additionally, we observed that restricting MM/PBSA calculations to ligands with a high degree of structural similarity to the crystal structure ligands improved performance in several cases. In conclusion, while MM/PBSA remains a valuable tool for GPCR structure-based drug design, its performance in predicting the binding free energies of GPCR ligands remains highly system-specific as demonstrated in a subset of twenty Class A GPCRs, and validation of MM/PBSA-based methods for each individual case is recommended before prospective use.
    Matched MeSH terms: Protein Conformation
  10. Molecular evolutionary and 3D protein structural analyses of Lactobacillus fermentum elongation factor Tu, a novel brain health promoting factor
    Ong JS, Liu YW, Liong MT, Choi SB, Tsai YC, Low WY
    Genomics, 2020 11;112(6):3915-3924.
    PMID: 32629096 DOI: 10.1016/j.ygeno.2020.06.052
    The role of microbiota in gut-brain communication has led to the development of probiotics promoting brain health. Here we report a genomic study of a Lactobacillus fermentum PS150 and its patented bioactive protein, elongation factor Tu (EF-Tu), which is associated with cognitive improvement in rats. The L. fermentum PS150 circular chromosome is 2,238,401 bp and it consists of 2281 genes. Chromosome comparisons with other L. fermentum strains highlighted a cluster of glycosyltransferases as potential candidate probiotic factors besides EF-Tu. Molecular evolutionary analyses on EF-Tu genes (tuf) in 235 bacteria species revealed one to three copies of the gene per genome. Seven tuf pseudogenes were found and three species only possessed pseudogenes, which is an unprecedented finding. Protein variability analysis of EF-Tu showed five highly variable residues (40 K, 41G, 42 L, 44 K, and 46E) on the protein surface, which warrant further investigation regarding their potential roles as binding sites.
    Matched MeSH terms: Protein Conformation
  11. Fulltext AnkPlex: algorithmic structure for refinement of near-native ankyrin-protein docking
    Wisitponchai T, Shoombuatong W, Lee VS, Kitidee K, Tayapiwatana C
    BMC Bioinformatics, 2017 Apr 19;18(1):220.
    PMID: 28424069 DOI: 10.1186/s12859-017-1628-6
    BACKGROUND: Computational analysis of protein-protein interaction provided the crucial information to increase the binding affinity without a change in basic conformation. Several docking programs were used to predict the near-native poses of the protein-protein complex in 10 top-rankings. The universal criteria for discriminating the near-native pose are not available since there are several classes of recognition protein. Currently, the explicit criteria for identifying the near-native pose of ankyrin-protein complexes (APKs) have not been reported yet.

    RESULTS: In this study, we established an ensemble computational model for discriminating the near-native docking pose of APKs named "AnkPlex". A dataset of APKs was generated from seven X-ray APKs, which consisted of 3 internal domains, using the reliable docking tool ZDOCK. The dataset was composed of 669 and 44,334 near-native and non-near-native poses, respectively, and it was used to generate eleven informative features. Subsequently, a re-scoring rank was generated by AnkPlex using a combination of a decision tree algorithm and logistic regression. AnkPlex achieved superior efficiency with ≥1 near-native complexes in the 10 top-rankings for nine X-ray complexes compared to ZDOCK, which only obtained six X-ray complexes. In addition, feature analysis demonstrated that the van der Waals feature was the dominant near-native pose out of the potential ankyrin-protein docking poses.

    CONCLUSION: The AnkPlex model achieved a success at predicting near-native docking poses and led to the discovery of informative characteristics that could further improve our understanding of the ankyrin-protein complex. Our computational study could be useful for predicting the near-native poses of binding proteins and desired targets, especially for ankyrin-protein complexes. The AnkPlex web server is freely accessible at http://ankplex.ams.cmu.ac.th .

    Matched MeSH terms: Protein Conformation
  12. ENRI: A tool for selecting structure-based virtual screening target conformations
    Akbar R, Jusoh SA, Amaro RE, Helms V
    Chem Biol Drug Des, 2017 May;89(5):762-771.
    PMID: 27995760 DOI: 10.1111/cbdd.12900
    Finding pharmaceutically relevant target conformations from an arbitrary set of protein conformations remains a challenge in structure-based virtual screening (SBVS). The growth in the number of available conformations, either experimentally determined or computationally derived, obscures the situation further. While the inflated conformation space potentially contains viable druggable targets, the increase of conformational complexity, as a consequence, poses a selection problem. To address this challenge, we took advantage of machine learning methods, namely an over-sampling and a binary classification procedure, and present a novel method to select druggable receptor conformations. Specifically, we trained a binary classifier on a set of nuclear receptor conformations, wherein each conformation was labeled with an enrichment measure for a corresponding SBVS. The classifier enabled us to formulate suggestions and identify enriching SBVS targets for six of seven nuclear receptors. Further, the classifier can be extended to other proteins of interest simply by feeding new training data sets to the classifier. Our work, thus, provides a methodology to identify pharmaceutically interesting receptor conformations for nuclear receptors and other drug targets.
    Matched MeSH terms: Protein Conformation
  13. Fulltext Structure of polyhydroxyalkanoate (PHA) synthase PhaC from Chromobacterium sp. USM2, producing biodegradable plastics
    Chek MF, Kim SY, Mori T, Arsad H, Samian MR, Sudesh K, et al.
    Sci Rep, 2017 07 13;7(1):5312.
    PMID: 28706283 DOI: 10.1038/s41598-017-05509-4
    Polyhydroxyalkanoate (PHA) is a promising candidate for use as an alternative bioplastic to replace petroleum-based plastics. Our understanding of PHA synthase PhaC is poor due to the paucity of available three-dimensional structural information. Here we present a high-resolution crystal structure of the catalytic domain of PhaC from Chromobacterium sp. USM2, PhaC Cs -CAT. The structure shows that PhaC Cs -CAT forms an α/β hydrolase fold comprising α/β core and CAP subdomains. The active site containing Cys291, Asp447 and His477 is located at the bottom of the cavity, which is filled with water molecules and is covered by the partly disordered CAP subdomain. We designated our structure as the closed form, which is distinct from the recently reported catalytic domain from Cupriavidus necator (PhaC Cn -CAT). Structural comparison showed PhaC Cn -CAT adopting a partially open form maintaining a narrow substrate access channel to the active site, but no product egress. PhaC Cs -CAT forms a face-to-face dimer mediated by the CAP subdomains. This arrangement of the dimer is also distinct from that of the PhaC Cn -CAT dimer. These findings suggest that the CAP subdomain should undergo a conformational change during catalytic activity that involves rearrangement of the dimer to facilitate substrate entry and product formation and egress from the active site.
    Matched MeSH terms: Protein Conformation
  14. Modelling of polyhydroxyalkanoate synthase from Aquitalea sp. USM4 suggests a novel mechanism for polymer elongation
    Teh AH, Chiam NC, Furusawa G, Sudesh K
    Int J Biol Macromol, 2018 Nov;119:438-445.
    PMID: 30048726 DOI: 10.1016/j.ijbiomac.2018.07.147
    Polyhydroxyalkanoate (PHA) synthase, PhaC, is a key enzyme in the biosynthesis of PHA, a type of bioplastics with huge potential to replace petroleum-based plastics. While two structures have been determined, the exact mechanism remains unclear partly due to the absence of a tunnel for product passage. A model of the class I PhaC from Aquitalea sp. USM4, characterised with Km of 394 μM and kcat of 476 s-1 on 3-(R)-hydroxybutyryl-CoA, revealed a three-branched channel at the dimeric interface. Two of them are opened to the solvent and are expected to serve as the putative routes for substrate entrance and product exit, while the third is elongated in the class II PhaC1 model from Pseudomonas aeruginosa, indicating a role in accommodating the hydroxyalkanoate (HA) moiety of a HA-CoA substrate. Docking of the two tetrahedral intermediates, formed during the transfer of the growing PHA chain from the catalytic Cys to a new molecule of substrate and back to Cys, suggests a common elongation mechanism requiring the HA moiety of the ligand to rotate ~180°. Substrate specificity is determined in part by a bulky Phe/Tyr/Trp residue in the third branch in class I, which is conserved as Ala in class II to create room for longer substrates.
    Matched MeSH terms: Protein Conformation
  15. Samira-VP: A simple protein alignment method with rechecking the alphabet vector positions
    Fotoohifiroozabadi S, Mohamad MS, Deris S
    J Bioinform Comput Biol, 2017 Apr;15(2):1750004.
    PMID: 28274174 DOI: 10.1142/S0219720017500044
    Protein structure alignment and comparisons that are based on an alphabetical demonstration of protein structure are more simple to run with faster evaluation processes; thus, their accuracy is not as reliable as three-dimension (3D)-based tools. As a 1D method candidate, TS-AMIR used the alphabetic demonstration of secondary-structure elements (SSE) of proteins and compared the assigned letters to each SSE using the [Formula: see text]-gram method. Although the results were comparable to those obtained via geometrical methods, the SSE length and accuracy of adjacency between SSEs were not considered in the comparison process. Therefore, to obtain further information on accuracy of adjacency between SSE vectors, the new approach of assigning text to vectors was adopted according to the spherical coordinate system in the present study. Moreover, dynamic programming was applied in order to account for the length of SSE vectors. Five common datasets were selected for method evaluation. The first three datasets were small, but difficult to align, and the remaining two datasets were used to compare the capability of the proposed method with that of other methods on a large protein dataset. The results showed that the proposed method, as a text-based alignment approach, obtained results comparable to both 1D and 3D methods. It outperformed 1D methods in terms of accuracy and 3D methods in terms of runtime.
    Matched MeSH terms: Protein Conformation
  16. Molecular Modeling and Simulation of Transketolase from Orthosiphon stamineus
    Ng ML, Rahmat ZB, Bin Omar MSS
    Curr Comput Aided Drug Des, 2019;15(4):308-317.
    PMID: 30345923 DOI: 10.2174/1573409914666181022141753
    BACKGROUND: Orthosiphon stamineus is a traditional medicinal plant in Southeast Asia countries with various well-known pharmacological activities such as antidiabetic, diuretics and antitumor activities. Transketolase is one of the proteins identified in the leaves of the plant and transketolase is believed able to lower blood sugar level in human through non-pancreatic mechanism. In order to understand the protein behavioral properties, 3D model of transketolase and analysis of protein structure are of obvious interest.

    METHODS: In the present study, 3D model of transketolase was constructed and its atomic characteristics revealed. Besides, molecular dynamic simulation of the protein at 310 K and 368 K deciphered transketolase may be a thermophilic protein as the structure does not distort even at elevated temperature. This study also used the protein at 310 K and 368 K resimulated back at 310 K environment.

    RESULTS: The results revealed that the protein is stable at all condition which suggest that it has high capacity to adapt at different environment not only at high temperature but also from high temperature condition to low temperature where the structure remains unchanged while retaining protein function.

    CONCLUSION: The thermostability properties of transketolase is beneficial for pharmaceutical industries as most of the drug making processes are at high temperature condition.

    Matched MeSH terms: Protein Conformation
  17. Metal substitutions incarbonic anhydrase: a halide ion probe study
    Smith RJ, Bryant RG
    Biochem Biophys Res Commun, 1975 Oct 27;66(4):1281-6.
    PMID: 3
    Matched MeSH terms: Protein Conformation
  18. Comparative structural analysis of fruit and stem bromelain from Ananas comosus
    Ramli ANM, Manas NHA, Hamid AAA, Hamid HA, Illias RM
    Food Chem, 2018 Nov 15;266:183-191.
    PMID: 30381175 DOI: 10.1016/j.foodchem.2018.05.125
    Cysteine proteases in pineapple (Ananas comosus) plants are phytotherapeutical agents that demonstrate anti-edematous, anti-inflammatory, anti-thrombotic and fibrinolytic activities. Bromelain has been identified as an active component and as a major protease of A. comosus. Bromelain has gained wide acceptance and compliance as a phytotherapeutical drug. The proteolytic fraction of pineapple stem is termed stem bromelain, while the one presents in the fruit is known as fruit bromelain. The amino acid sequence and domain analysis of the fruit and stem bromelains demonstrated several differences and similarities of these cysteine protease family members. In addition, analysis of the modelled fruit (BAA21848) and stem (CAA08861) bromelains revealed the presence of unique properties of the predicted structures. Sequence analysis and structural prediction of stem and fruit bromelains of A. comosus along with the comparison of both structures provides a new insight on their distinct properties for industrial application.
    Matched MeSH terms: Protein Conformation
  19. Fulltext Chitinase: diversity, limitations, and trends in engineering for suitable applications
    Oyeleye A, Normi YM
    Biosci Rep, 2018 Sep 03;38(4).
    PMID: 30042170 DOI: 10.1042/BSR20180323
    Chitinases catalyze the degradation of chitin, a ubiquitous polymer generated from the cell walls of fungi, shells of crustaceans, and cuticles of insects. They are gaining increasing attention in medicine, agriculture, food and drug industries, and environmental management. Their roles in the degradation of chitin for the production of industrially useful products and in the control of fungal pathogens and insect pests render them attractive for such purposes. However, chitinases have diverse sources, characteristics, and mechanisms of action that seem to restrain optimization procedures and render standardization techniques for enhanced practical applications complex. Hence, results of laboratory trials are not usually consistent with real-life applications. With the growing field of protein engineering, these complexities can be overcome by modifying or redesigning chitinases to enhance specific features required for specific applications. In this review, the variations in features and mechanisms of chitinases that limit their exploitation in biotechnological applications are compiled. Recent attempts to engineer chitinases for improved efficiency are also highlighted.
    Matched MeSH terms: Protein Conformation
  20. Fulltext Computational identification of 4-carboxyglutamate sites to supplement physiological studies using deep learning
    Naseer S, Ali RF, Fati SM, Muneer A
    Sci Rep, 2022 01 07;12(1):128.
    PMID: 34996975 DOI: 10.1038/s41598-021-03895-4
    In biological systems, Glutamic acid is a crucial amino acid which is used in protein biosynthesis. Carboxylation of glutamic acid is a significant post-translational modification which plays important role in blood coagulation by activating prothrombin to thrombin. Contrariwise, 4-carboxy-glutamate is also found to be involved in diseases including plaque atherosclerosis, osteoporosis, mineralized heart valves, bone resorption and serves as biomarker for onset of these diseases. Owing to the pathophysiological significance of 4-carboxyglutamate, its identification is important to better understand pathophysiological systems. The wet lab identification of prospective 4-carboxyglutamate sites is costly, laborious and time consuming due to inherent difficulties of in-vivo, ex-vivo and in vitro experiments. To supplement these experiments, we proposed, implemented, and evaluated a different approach to develop 4-carboxyglutamate site predictors using pseudo amino acid compositions (PseAAC) and deep neural networks (DNNs). Our approach does not require any feature extraction and employs deep neural networks to learn feature representation of peptide sequences and performing classification thereof. Proposed approach is validated using standard performance evaluation metrics. Among different deep neural networks, convolutional neural network-based predictor achieved best scores on independent dataset with accuracy of 94.7%, AuC score of 0.91 and F1-score of 0.874 which shows the promise of proposed approach. The iCarboxE-Deep server is deployed at https://share.streamlit.io/sheraz-n/carboxyglutamate/app.py .
    Matched MeSH terms: Protein Conformation
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